Re: [PATCH v4 1/2] dt-bindings: firmware: arm,scmi: Document arm,no-completion-irq property

[Rob Herring <robh@kernel.org>]

On Mon, Jan 19, 2026 at 05:02:58PM +0000, Sudeep Holla wrote:
> On Mon, Jan 19, 2026 at 04:53:45PM +0000, Cristian Marussi wrote:
> > On Sat, Jan 17, 2026 at 02:02:28AM +0100, Marek Vasut wrote:
> > > Document new property arm,no-completion-irq . This optional property
> > > is intended for hardware that does not generate completion interrupts
> > > and can be used to unconditionally enable forced polling mode of
> > > operation.
> > > 
> > > With this property set, such implementations which do not generate
> > > interrupts can be interacted with, until they are fixed to generate
> > > interrupts properly.
> > > 
> > > Note that, because the original base protocol exchange also requires
> > > some sort of completion mechanism, it is not possible to query SCMI
> > > itself for this property and it must be described in DT. While this
> > > does look a bit like policy, the SCMI provider is part of the
> > > hardware, hence DT.
> > > 
> > > Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
> > > Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> > > ---
> > > Cc: Conor Dooley <conor+dt@kernel.org>
> > > Cc: Cristian Marussi <cristian.marussi@arm.com>
> > > Cc: Florian Fainelli <florian.fainelli@broadcom.com>
> > > Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> > > Cc: Rob Herring <robh@kernel.org>
> > > Cc: Sudeep Holla <sudeep.holla@arm.com>
> > > Cc: arm-scmi@vger.kernel.org
> > > Cc: devicetree@vger.kernel.org
> > > Cc: linux-arm-kernel@lists.infradead.org
> > > Cc: linux-renesas-soc@vger.kernel.org
> > > ---
> > > V2: s@mean@&t and limit poll transport to mailbox/shmem only
> > > V3: - Reformat the commit message, expand property description to
> > >       explicitly spell out this is hardware description.
> > >     - Rename property from arm,poll-transport to arm,no-completion-irq
> > > V4: - Update first paragraph of commit message and property description
> > >     - Add RB from Rob
> > > ---
> > >  .../devicetree/bindings/firmware/arm,scmi.yaml         | 10 ++++++++++
> > >  1 file changed, 10 insertions(+)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> > > index be817fd9cc34b..d06cca9273c48 100644
> > > --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> > > +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> > > @@ -146,6 +146,13 @@ properties:
> > >        this platform. If set, the value should be non-zero.
> > >      minimum: 1
> > >  
> > > +  arm,no-completion-irq:
> > > +    type: boolean
> > > +    description:
> > 
> > Shouldn't these two points have to be swapped as per Sudeep and Rob
> > suggestions ?
> > 
> >     description:
> > 	....
> >     type: boolean
> > 
> 
> I was just referring to the points covered under the `description` and not
> the order of `type` and `description`. I am not sure if there is any such
> requirement as well.

There isn't. The only preference is to be consistent within a file of 
description either first or last.

Rob